问题：

[单选]

You have configured the following： 
RMAN> CONFIGURE DEFAULT DEVICE TYPE TO ’sbt’； new RMAN configuration parameters： 
CONFIGURE DEFAULT DEVICE TYPE TO ’sbt’； new RMAN configuration parameters are successfully stored
RMAN> SHOW DEVICE TYPE； RMAN configuration parameters are： CONFIGURE DEVICE TYPE SBT PARALLELISM 1； # CONFIGURE DEVICE TYPE DISK PARALLELISM 1； # 
RMAN> CONFIGURE DEVICE TYPE SET PARALLELISM 5； 
RMAN> SHOW DEVICE TYPE； RMAN configuration parameters are： CONFIGURE DEVICE TYPE SBT PARALLELISM 5； CONFIGURE DEVICE TYPE DISK PARALLELISM 1； # 
How many channels are allocated to SBT？（）

A . 0， because channels have not been defined.
B . 3， as indicated by the degree of parallelism.
C . 1， the default value when device is configured.
D . 5， as indicated by the last parallelism command.